Housing for electroacoustical apparatus



Oct. 24, 1950 H. c. HAYES HOUSING FOR ELECTROACOUSTICAL APPARATUS Filed April 8, 1936 INVENTOR Harvey C Hayes A TTORNEY Patented Oct. 24, 1950 2,527,217 p HOUSING FOR ELECTROACOUSTICAL APPARATUS Harvey Hayes, Washington; D,- Application April s, 1936, s am- 73,389 (01. 181-5) I I (Granted under the act of March, 3, 1883, as,

12 Claims.

amended April 30, 1928; 37010;, 757) My invention relates to devices for transmit! ting and/or receiving sound, in a fluid medium of water and the like. Such devicesusually comprise a fluid tight casing havin inclosed-there-- in the sound transmitting or receiving means and, if the device is to operate for transmitting or receiving sound directed about a horizontal plane, it is mounted on a vertical tubing for rotational movement. In operation the device is projected by means ofthe vertical tubing into the fluid medium and is held aligned by bearings carried in a sea chest inclosing the opening in the ships envelope.

The Shape of the sound transmitting and/or receiving means is usually such that the inclosing casing may be made cylindrical in form, the casing being mounted on" the: vertical supporting tubin with its cylindrical axis. perpendicular to that of the tubing so that the sound activeiarea of the casing will face horizontally. This type of sound transmitting and/or receiving'devicehas' been satisfactory while being moved through water at lower speeds, but it has notproved to be an efficient device at speedsabovenine-knots and higher due to the development of both acoustical and mechanical diihculties. I

The earlier device was poorly streamlined and generated a violent turbulent envelope aboutitself at higher speeds whichimpededsound transit to and therefrom, thus lowering the accoustica-l efllciency. Furthermore, the turbulence itself generated sufllcienthigh pitched sound to give a orient itself rigidly acrossthelines of flowwithin the fluid medium,;thus making it extremely di f-,

ficult, to rotate the device from this position.v

With the foregoing deficiencies in view, it is an, object-of hey-invention toreduce to asminimum, the acoustical,difflcultiesencountered by move:

ments of the, device high speeds; a, V

It is another object oi?-v my invention to also. reduce to a minimum theniechanical difiiculties within a: fluid medium at,

attending the movements; of such a device ina fluid medium, at high speeds. .v a With the; above and; other objects in view, the inventionconsists in the construction, combinaa tion, and arrangements of parts aswill be=dew scribed more-fully hereinafter.

In=the;drawing s:; 1

Figs 1 is=a view in elevation of'asoundreceive ing and/ortransmitting device-now in use;

Fig. 2 is a'view inpartial section taken-along loud background of noise inthe receiver-which,-

tended to mask such sound as did penetrateand prevented its being heard, Therefore, it is ap-' parent that any expedient which will reduce to a minimum the turbulent layer incidental to movements of translation of the device in the fluid medium will improve its efiiciency'in that'it will.

permit sound signals to pass to and from the device with less attenuation and cut down the background of noise so as to make the'weaker signals audible.

The lack of streamlining in addition: presents a series of mechanical difilculties at the higher speeds and are directly traceable to the fluid pressure on the device which is greater than it would be if streamlining were employed. This excessive pressure results in imposing undue strains on the supporting tubing and greater pressure on the bearings, accompanied with greater diiflculty in rotatin the same. Furthermore; the lack of symmetry about? the vertical axis of rotation. of the cylindrical casing creates a tendency of the! device: athigher-speeds to Fig. 4 isaa; view impartial section of another embodiment of my invention.

RBfBIIiIIg-DOW-tOrEigS; 1? and 2, it will be noted that'the :devicein-- present use comprises general- 1yv a cylindrical casingrzhavings a sound sensitive area hand. a closure 3. removably associated therewithiinfluid-tightrelation. "The upper p0r-.' tionaof; thecasingis providedwitha flange 4 which. i s-bolted'or secured in any other suitable manner toacorresponding flange of the vertical supports ing tube; Thecylindrica-l axis ofthe casing, as isevident fromaninspection of the drawings, is perpendicular to that of the vertical supporting tubing; :Electrical'leads 5 extend from the ver+ tical tubing througha stufling-box 6 into'the casing; to thereby; connectin circuit, theelectroacousticalenergy-- interchanging means denotedin general bythle numeral? which may be eithera-soundtransmittin orsound receiving means or a means combiningboth of these functions.

In order'to reduce to a minimum the acoustical and mechanical difficulties incidental to movements of' translation and rotation of theiaforementioned devices in a fluid medium at therei-v atively higher speeds, I have in accordance with my invention-made: the outline of-"the casing or housinggthat meets the water, or other fluid medium, fi -surface of revolution about the vertical supporting tubing. Such a casing or housing, whil not perfectly streamlined, gives as good a stream-lining; as an bee pected tor a body at once apparent to those skilled in the art, need not be spherical but may if desired be ellipsoidal or cylindrical in contour or any other form so long 7 as it meets the requirements that it be a surface of revolution about the axis of the vertical supporting tubing. This housing comprises a metal cylindrical member l2 on one side of which there is removably secured a fluid tight closure l3. The

remaining portions of the housing are fashioned of a sound transparent material concerning which more particular reference will be made hereinafter. A segment l5 of the sound transparent material is made so that it can be removed, thus rendering the closure member previously referred to accessible. The electro-acoustical energy interchanging means, designated generally by the numeral I4, is mounted within the housing in a manner similar to that described in connection with the device of Figs. 1 and 2. Furthermore, the medium within the housing interior must have such propagational constants that it will not produce distortion of the sound beam.

The material of that portion of the housing interposed between the active area of the electroacoustical energy interchanging means and the surrounding fluid medium should have the same acoustical impedance as the fluid medium so as to insure the maximum ease of sound transfer to and from the said area. At least the segmental housing portion l 6 is sound transparent and can be made of water-soaked wood but is preferably made of one of the rubber compounds whichI have developed for this purpose. Such a rubber compound, if properly processed, transmits the sound with practically the same velocity as does the surrounding water, thus avoiding any distortion of the wave front due to the shape of the segmental housing portion. However, in order to avoid the extreme care required in the vulcanizing process to assure that this segmentalhousing portion does not introduce any distortion in the wave front, I have tested and as a result prefer the embodiment shown in Fig. 4 of the drawings wherein the segmental housing portion I I through which the sound wave must pass is so fashioned that the thickness of the rubber compound tra versed by all portions of the plane wave front,- leaving the active face or approaching the same, is con tant. By adopting such an expedient no great pains need be exercised during the vulcanizing process. The embodiment of Fig. 4 with this one exception is otherwise the same in structure as the device shown in Fig. 3. 1

According to the provisions of the patent stat utes, I have explained the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

This invention may be manufactured and used by the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. A device of the character described operable for both movements of translation and rotation in a liquid medium, comprising in combination electro-mechanical energy interchanging means, liquid impervious means enveloping said first mentioned means, said enveloping means having a surface contour offering a minimum of resistanceto movements of translation of said device through the'liq'uidl medium consistent with rotational movement of the same and being at least in part of a material having an acoustical impedance sub tantially equal to that of the surrounding liquid medium.

2. A device of the character described operable for both movements of translation and rotaan. A)

tion in a liquid medium, comprising in combination electro-mechanical energy interchanging means, means for reducing to a minimum fluid turbulence and liquid pressure incidental to movements of translation in the fluid medium, said second mentioned means enveloping said first mentioned means in liquid tight relation and being at least in part of a material having an acoustical impedance substantially equal to that of the surrounding liquid medium.

3. A device of the character described operable for movements of translation in a liquid medium, comprising in combination electro-mechanical energy interchanging means, liquid impervious means for enveloping said first mentioned means and for reducing to a minimum liquid turbulence-v incidental to 'movements of translation in the liquid medium', said seco'nd'mentioned means being at least in part of a material having an acous tical impedance substantially equal to that of the surrounding liquid medium.

4. A device of the character described operable for movements of translation in a liquid medium; in combination electromechanical comprising energy interchanging means, liquid impervious means for enveloping said ffi'rst mentioned means; and for reducing to a minimum liquid pressure incidental to movements .of translation in the.

liquid medium,'said secondmentioned means being at least in part era material, having an ac-' coustical impedance substantially equal to that of the surrounding liquid medium.

5. A device of the character described operable for both movements of translation and rotation in a liquid medium, comprising in combination electro-mechanical energy interchanging means, liquid impervious means for enveloping said first mentioned means and'for obviating any tendency of the device to set-itself rigidly across the lines of flow in the liquid medium to thereby reduce to a minimum any difficulty of rotational movement of said device, said second mentioned means being at least in part of 'a'material having an acoustical impedance substantially equal to that of the surrounding liquid medium. 1

6. A liquid impervious housing for electro-- acoustical energy interchanging means and operable for both movementsof translation and movements of rotation about a vertical axis in a liquid medium, said housing having a contour in contact with the liquid medium which is that of a surface of revolution about the vertical axis of rotation of the housing and being at least in part of a material having an acoustical impedance substantially equal to that of the surrounding fluid medium.

'7. A liquid impervious housing for electroacoustical energy interchanging means and operable for both movements of translation and movements of rotation about a vertical axis in a liquid medium, said housing having a contour in contact with the'liquid medium which is that of a surface. of revolution about the vertical axis of rotation of the housing, the acoustically active portion of the housing having a substantially uniform thickness for all portions of a plane wave front traversing said active portion of said housing and at least this portion of the housing being of a material having an acoustical impedance similar to that of the surrounding liquid medium.

8. A liquid impervious, spherically shaped housing for electro-acoustical energy interchanging means and operable for both movements of translation and movements of rotation about a vertical axis in a liquid medium, the acoustically active portion of this housing having a substantially uniform thickness for all portions of a plane wave front traversing the said acoustically active portion of said housing and at least this portion of the housing bein of a material having an acoustical impedance similar to that of the surrounding liquid medium.

9. A liquid impervious housing for electroacoustical energy interchanging means and operable for both movements of translation and movements of rotation about a vertical axis in a liquid medium, the acoustically active portion of this housing having a. substantially uniform thickness for all portions of a plane wave front traversing the said acoustically active portion of said housing and at least this portion of the housing being of a material having an acoustical impedance similar to that of the surrounding liquid medium.

10. A liquid impervious housing for electroacoustical energy interchanging means having an outer configuration substantially that of a surface of revolution and operable for both movements of translation and movements of rotation about a vertical axis in' a liquid medium, the acoustically active portion or the housing having a. substantially uniform'thickness for allportions i of a plane wave front traversing the said acoustically active portion of said housing andat leastv this portion of the housing being ofa material having an acoustical impedance similar to that stantially equal to that of the surrounding liquid medium. a Y Y V HARVEY o. HAYES. REFERENCES CITED The following references are of record in the" file of this patent:

UNITED STATES PATENTS Number Name Date i 768,573 Mundy Aug. 23, 1904 FOR IGN PATENTS Number Country bate 131,038 Great Britain 1918' 

